Impact of trametinib on the neuropsychological profile of NF1 patients.

PURPOSE: The use of trametinib in the treatment of pediatric low-grade gliomas (PLGG) and plexiform neurofibroma (PN) is being investigated in an ongoing multicenter phase II trial (NCT03363217). Preliminary data shows potential benefits with significant response in the majority of PLGG and PN and an overall good tolerance. Moreover, possible benefits of MEK inhibitor therapy on cognitive functioning in neurofibromatosis type 1 (NF1) were recently shown which supports the need for further evaluation. METHODS: Thirty-six patients with NF1 (age range 3-19 years) enrolled in the phase II study of trametinib underwent a neurocognitive assessment at inclusion and at completion of the 72-week treatment. Age-appropriate Wechsler Intelligence Scales and the Trail Making Test (for children over 8 years old) were administered at each assessment. Paired t-tests and Reliable Change Index (RCI) analyses were performed to investigate change in neurocognitive outcomes. Regression analyses were used to investigate the contribution of age and baseline score in the prediction of change. RESULTS: Stable performance on neurocognitive tests was revealed at a group-level using paired t-tests. Clinically significant improvements were however found on specific indexes of the Wechsler intelligence scales and Trail Making Test, using RCI analyses. No significant impact of age on cognitive change was evidenced. However, lower initial cognitive performance was associated with increased odds of presenting clinically significant improvements on neurocognitive outcomes. CONCLUSION: These preliminary results show a potential positive effect of trametinib on cognition in patients with NF1. We observed significant improvements in processing speed, visuo-motor and verbal abilities. This study demonstrates the importance of including neuropsychological evaluations into clinical trial when using MEK inhibitors for patients with NF1.

Development of a semi-automatic segmentation technique based on mean magnetic resonance imaging intensity thresholding for volumetric quantification of plexiform neurofibromas.

Rationale and objectives: Plexiform neurofibromas (PNs) are peripheral nerve tumors that occur in 25-50 % of patients with neurofibromatosis type 1. PNs may have complex, diffused, and irregular shapes. The objective of this work was to develop a volumetric quantification method for PNs as clinical assessment is currently based on unidimensional measurement. Materials and methods: A semi-automatic segmentation technique based on mean magnetic resonance imaging (MRI) intensity thresholding (SSTMean) was developed and compared to a similar and previously published technique based on minimum image intensity thresholding (SSTMini). The performance (volume and computation time) of the two techniques was compared to manual tracings of 15 tumors of different locations, shapes, and sizes. Performance was also assessed using different MRI sequences. Reproducibility was assessed by inter-observer analysis. Results: When compared to manual tracing, quantification performed with SSTMean was not significantly different (mean difference: 1.2 %), while volumes computed by SSTMini were significantly different (p < .0001, mean difference: 13.4 %). Volumes quantified by SSTMean were also significantly different than the ones assessed by SSTMini (p < .0001). Using SSTMean, volumes quantified with short TI inversion recovery, T1-, and T2-weighted imaging were not significantly different. Computation times used by SSTMean and SSTMini were significantly lower than for manual segmentation (p < .0001). The highest difference measured by two users was 8 cm3. Conclusion: Our method showed accuracy compared to a current gold standard (manual tracing) and reproducibility between users. The refined segmentation threshold and the possibility to define multiple regions-of-interest to initiate segmentation may have contributed to its performance. The versatility and speed of our method may prove useful to better monitor volumetric changes in lesions of patients enrolled in clinical trials to assessing response to therapy.

Opioid analgesia and temperature regulation are associated with EEG background activity and MRI outcomes in neonates with mild-to-moderate hypoxic-ischemic encephalopathy undergoing therapeutic hypothermia.

BACKGROUND: Therapeutic hypothermia (TH) without sedation may lead to discomfort, which may be associated with adverse consequences in neonates with hypoxic-ischemic encephalopathy (HIE). The aim of this study was to assess the association between level of exposure to opioids and temperature, with electroencephalography (EEG) background activity post-TH and magnetic resonance imaging (MRI) brain injury in neonates with HIE. METHODS: Thirty-one neonates with mild-to-moderate HIE who underwent TH were identified. MRIs were reviewed for presence of brain injury. Quantitative EEG background features including EEG discontinuity index and spectral power densities were calculated during rewarming and post-rewarming periods. Dose of opioids administered during TH and temperatures were collected from the medical charts. Multivariable linear and logistic regression analyses were conducted to assess the associations between cumulative dose of opioids and temperature with EEG background and MRI while adjusting for markers of HIE severity. RESULTS: Higher opioid doses (ß = -0.21, p = 0.02) and reduced skin temperature (ß = 0.14, p < 0.01) were associated with lower EEG discontinuity index recorded post-TH. Higher opioid doses (ß = 0.75, p = 0.01) and reduced skin temperature (ß = -0.39, p = 0.02) were also associated with higher EEG Delta power post-TH. MRI brain injury was observed in 14 patients (45%). In adjusted regression analyses, higher opioid doses (OR = 0.00; 95%CI: 0-0.19; p = 0.01), reduced skin temperature (OR = 41.19; 95%CI: 2.27-747.86; p = 0.01) and reduced cooling device output temperature (OR = 1.91; 95%CI: 1.05-3.48; p = 0.04) showed an association with lower odds of brain injury. CONCLUSIONS: Higher level of exposure to opioids and reduced skin temperature during TH in mild-to-moderate HIE were associated with improved EEG background activity post-TH. Moreover, higher exposure to opioids, reduced skin temperature and reduced device output temperature were associated with lower odds of brain injury on MRI.

Infantile onset carnitine palmitoyltransferase 2 deficiency: Cortical polymicrogyria, schizencephaly, and gray matter heterotopias in an adolescent with normal development.

OBJECTIVE: To report an adolescent with infantile-onset carnitine palmitoyltransferase 2 (CPT2) deficiency and cerebral malformations and to review the occurrence of brain malformations in CPT2 deficiency. The patient presented clinically at age 5 months with dehydration and hepatomegaly. He also has an unrelated condition, X-linked nephrogenic diabetes insipidus. He had recurrent rhabdomyolysis but normal psychomotor development. At age 17 years, he developed spontaneous focal seizures. Cerebral magnetic resonance imaging revealed extensive left temporo-parieto-occipital polymicrogyria, white matter heterotopias, and schizencephaly. Neuronal migration defects were previously reported in lethal neonatal CPT2 deficiency but not in later-onset forms. DESIGN AND METHODS: We searched PubMed, Google Scholar, and the bibliographies of the articles found by these searches, for cerebral malformations in CPT2 deficiency. All antenatal, neonatal, infantile, and adult-onset cases were included. Exclusion criteria included insufficient information about age of clinical onset and lack of confirmation of CPT2 deficiency by enzymatic assay or genetic testing. For each report, we noted the presence of cerebral malformations on brain imaging or pathological examination. RESULTS: Of 26 neonatal-onset CPT2-deficient patients who met the inclusion criteria, brain malformations were reported in 16 (61.5%). In 19 infantile-onset cases, brain malformations were not reported, but only 3 of the 19 reports (15.8%) include brain imaging or neuropathology data. In 276 adult-onset cases, no brain malformations were reported. CONCLUSION: To the best of our knowledge, this is the first report of cerebral malformations in an infantile onset CPT2-deficient patient. Brain imaging should be considered in patients with CPTII deficiency and neurological manifestations, even in those with later clinical onset.

A phase 2 study of trametinib for patients with pediatric glioma or plexiform neurofibroma with refractory tumor and activation of the MAPK/ERK pathway: TRAM-01.

BACKGROUND: Pediatric low-grade gliomas (PLGG) are the most frequent brain tumors in children. Up to 50% will be refractory to conventional chemotherapy. It is now known that the majority of PLGG have activation of the MAPK/ERK pathway. The same pathway is also activated in plexiform neurofibromas (PNs) which are low-grade tumors involving peripheral nerves in patients with neurofibromatosis type 1 (NF1). These lesions are known to be refractory to chemotherapy. Specific MEK inhibitors such as trametinib are now available and have been approved for other cancers harboring mutations in the MAPK/ERK pathway such as melanoma. We have observed significant responses to trametinib in patients with refractory PLGG in our institutions and results from the phase I study are promising. The treatment appears not only efficacious but is also usually well tolerated. We hypothesize that we will observe responses in the majority of refractory PLGG and PN treated with trametinib in this phase 2 study. METHODS: The primary objective is to determine the objective response rate of trametinib as a single agent for treatment of progressing/refractory tumors with MAPK/ERK pathway activation. The TRAM-01 study is a phase II multicentric open-label basket trial including four groups. Group 1 includes NF1 patients with progressing/refractory glioma. Group 2 includes NF1 patients with plexiform neurofibroma. Group 3 includes patients with progressing/refractory glioma with KIAA1549-BRAF fusion. Group 4 includes other patients with progressing/refractory glioma with activation of the MAPK/ERK pathway. Eligible patients for a given study group will receive daily oral trametinib at full dose for a total of 18 cycles of 28 days. A total of 150 patients will be enrolled in seven Canadian centers. Secondary objectives include the assessment of progression-free survival, overall survival, safety and tolerability of trametinib, serum levels of trametinib and evaluation of quality of life during treatment. DISCUSSION: Trametinib will allow us to target directly and specifically the MAPK/ERK pathway. We expect to observe a significant response in most patients. Following our study, trametinib could be integrated into standard treatment of PLGG and PN. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03363217 December 6, 2017.

18F-Flurodeoxyglucose positron emission tomography with computed tomography (FDG PET/CT) findings in children with encephalitis and comparison to conventional imaging.

PURPOSE: FDG PET/CT is emerging as a new tool for the evaluation of acute encephalitis (AE). However, to date, there are no exclusively pediatric studies on the use of FDG PET for suspected AE. The objective of this study was to compare qualitative and quantitative brain PET to conventional brain imaging in a cohort of children, and to identify patterns of metabolic abnormalities characteristic of AE. METHODS: This retrospective study included 34 children imaged with PET/CT, CT and magnetic resonance imaging (MRI). The positivity rate of all three imaging modalities was measured. Besides visual assessment, quantification of relative regional brain metabolism (RRBM) was performed and compared to a database of normal pediatric brains. RESULTS: Fourteen subjects had a clinical diagnosis of autoimmune encephalitis (AIE) or encephalitis of unknown origin (EX), six of anti-N-methyl-D-aspartate receptor (anti-NMDAr) encephalitis, three of Hashimoto's encephalopathy, three of neurolupus and eight had other subtypes of encephalitis. Quantitative PET was abnormal in 100% of cases, visually assessed PET in 94.1% of subjects, MRI in 41.2% and CT in 6.9%. RRBM quantification demonstrated multiple hyper and hypo metabolic cortical regions in 82.3% of subjects, exclusively hypermetabolic abnormalities in 3%, and exclusively hypometabolic abnormalities in 14.7%. The basal ganglia were hypermetabolic in 26.5% of cases on visual assessment and in 58.8% of subjects using quantification. CONCLUSION: In our pediatric population FDG PET was more sensitive than conventional imaging for the detection of AE, and basal ganglia hypermetabolism was frequently encountered.

Intracranial hypertension following sacrifice of occipital and marginal sinuses during posterior fossa decompression for Chiari I malformation: case report.

The occipital and marginal sinuses, when present, must be sacrificed in order to open the dura in most posterior fossa surgeries in the pediatric population, including posterior fossa decompression for Type I Chiari malformation (CM-I) with duraplasty. Apart from the immediate risk of hemorrhage, the voluntary occlusion of this structure is almost universally well tolerated. The authors report a case of intracranial hypertension following the sacrifice of occipital and marginal sinuses following posterior fossa decompression with duraplasty for CM-I. The specific draining pattern variant of the occipital and marginal sinuses leading to this complication as well as avoidance and management strategies of this condition are discussed.

Dissecting spontaneous cerebrospinal fluid collection.

Hydrocephalus is a common condition in the pediatric population known to have many causes and presentation patterns. We report from the analysis of 2 cases the existence of a new complication of pediatric hydrocephalus. Naming this entity "dissecting intraparenchymal cerebrospinal fluid collection", we advance a hypothesis regarding its pathophysiology and discuss its clinical implications and management.

Imaging of Acquired Demyelinating Syndrome With 18F-FDG PET/CT.

Acquired demyelinating syndromes include acute disseminated encephalomyelitis, transverse myelitis and may progress to multiple sclerosis (MS). Acute disseminated encephalomyelitis is characterized by impairment of level of consciousness and multifocal neurological deficits and transverse myelitis by back pain, weakness and sphincter dysfunction. Only a few cases of acquired demyelinating syndrome have been imaged with F-FDG PET/CT. We present two such cases.

Identification and functional characterization of a novel MTFMT mutation associated with selective vulnerability of the visual pathway and a mild neurological phenotype.

Mitochondrial protein synthesis is initiated by formylated tRNA-methionine, which requires the activity of MTFMT, a methionyl-tRNA formyltransferase. Mutations in MTFMT have been associated with Leigh syndrome, early-onset mitochondrial leukoencephalopathy, microcephaly, ataxia, and cardiomyopathy. We identified compound heterozygous MTFMT mutations in a patient with a mild neurological phenotype and late-onset progressive visual impairment. MRI studies documented a progressive and selective involvement of the retrochiasmatic visual pathway. MTFMT was undetectable by immunoblot analysis of patient fibroblasts, resulting in specific defects in mitochondrial protein synthesis and assembly of the oxidative phosphorylation complexes. This report expands the clinical and MRI phenotypes associated with MTFMT mutations, illustrating the complexity of genotype-phenotype relationships in mitochondrial translation disorders.

Significant motor improvement in an infant with congenital heart disease and a rolandic stroke: The impact of early intervention.

OBJECTIVE: To report the impact of early motor intervention in an infant with congenital heart disease (CHD) and a stroke. METHODS AND RESULTS: A 35-week newborn with a complex CHD and a normal MRI presented with early motor developmental delay at 2 months. She began an intervention program, which included biweekly motor developmental therapy with a physiotherapist, parental education, and daily home exercises. At 4 months, she underwent cardiac surgery. Following surgery, she was diagnosed with a stroke involving the right sylvian artery territory. She continued her intensive intervention program. The 12-month assessment revealed an evident gain of motor function. Despite MRI evidence of a chronic infarct involving the primary motor cortex, the child had normal motor functions. CONCLUSION: This case report supports the positive impact of early intervention in infants with CHD and its potential effect on enhancing neuroplasticity, even in children with cerebro-vascular accidents involving areas of motor function.

A Phase II feasibility study of oral etoposide given concurrently with radiotherapy followed by dose intensive adjuvant chemotherapy for children with newly diagnosed high-risk medulloblastoma (protocol POG 9631): A report from the Children's Oncology Group.

BACKGROUND: Children with high-risk medulloblastoma historically have had a poor prognosis. The Children's Oncology Group completed a Phase II study using oral etoposide given with radiotherapy followed by intensive chemotherapy. PROCEDURE: Patients enrolled in the study had high-risk disease defined as ≥1.5 cm2 of residual disease postsurgery or definite evidence of central nervous metastasis. All patients underwent surgery followed by radiotherapy. During radiation, the patients received oral etoposide (21 days on, 7 off) at an initial dose of 50 mg/m2 per day (treatment 1), which was reduced to 35 mg/m2 per day (treatment 2) due to toxicity. After radiotherapy, the patients received chemotherapy with three cycles of cisplatin and oral etoposide, followed by eight courses of cyclophosphamide and vincristine. RESULTS: Between November 1998 and October 2002, 53 patients were accrued; 15 received treatment 1 and 38 treatment 2. Forty-seven patients (89%) were eligible. Response to radiation was excellent, with 19 (40.4%) showing complete response, 24 (51.1%) partial response, and four (8.5%) no recorded response. The overall 2- and 5-year progression-free survival (PFS) was 76.6 ± 6% and 70.2 ± 7%, respectively. The 2- and 5-year overall survival (OS) was 80.9 ± 6% and 76.6 ± 6%, respectively. Clinical response postradiation and PFS/OS were not significantly different between the treatment groups. There was a trend toward a difference in 5-year PFS between those without and with metastatic disease (P = 0.072). CONCLUSIONS: Oral etoposide was tolerable at 35 mg/m2 (21 days on and 7 days off) when given during full-dose irradiation in patients with high-risk medulloblastoma with encouraging survival data.

Predictive Factors for Epilepsy in Pediatric Patients With Sturge-Weber Syndrome.

BACKGROUND: Sturge-Weber syndrome is characterized by a facial port-wine stain associated with either or both a retinal angioma and a cerebral pial angioma. Because a pial angioma may not be evident on the initial imaging studies, individuals at risk for epilepsy are often not identified before their first seizure. The aim of this study is to identify predictive factors predisposing Sturge-Weber patients to epilepsy. METHODS: The medical archives and photography database of our institution were reviewed to identify Sturge-Weber Syndrome patients followed up between 1990 and 2015. Patients without epilepsy were compared with patients with epilepsy based on the location of the port-wine stain, its extent and cerebral imaging. RESULTS: Twenty-four patients were included in the study. Thirteen did not develop epilepsy. Patients with bilateral port-wine stain were at higher risk of epilepsy (P = 0.03). Unilateral port-wine stain did not increase the risk of epilepsy (P = 0.29) regardless of its extent. The presence of developmental venous anomalies on brain imaging was also associated with a higher risk of epilepsy (P = 0.03). CONCLUSIONS: Bilateral facial port-wine stain and cerebral developmental venous anomalies increase the risk of epilepsy in Sturge-Weber syndrome patients. Because they can be detected at birth, they might guide preventive management and follow-up.

Rewarming affects EEG background in term newborns with hypoxic-ischemic encephalopathy undergoing therapeutic hypothermia.

OBJECTIVE: To investigate how rewarming impacts the evolution of EEG background in neonates with hypoxic-ischemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH). METHODS: We recruited a retrospective cohort of 15 consecutive newborns with moderate (9) and severe (6) HIE monitored with a continuous EEG during TH and at least 12h after its end. EEG background was analyzed using conventional visual and quantitative EEG analysis methods including EEG discontinuity, absolute and relative spectral magnitudes. One patient with seizures on rewarming was excluded from analyses. RESULTS: Visual and quantitative analyses demonstrated significant changes in EEG background from pre- to post-rewarming, characterized by an increased EEG discontinuity, more pronounced in newborns with severe compared to moderate HIE. Neonates with moderate HIE also had an increase in the relative magnitude of slower delta and a decrease in higher frequency theta and alpha waves with rewarming. CONCLUSIONS: Rewarming affects EEG background in HIE newborns undergoing TH, which may represent a transient adaptive response or reflect an evolving brain injury. SIGNIFICANCE: EEG background impairment induced by rewarming may represent a biomarker of evolving encephalopathy in HIE newborns undergoing TH and underscores the importance of continuously monitoring the brain health in critically ill neonates.

Joubert Syndrome in French Canadians and Identification of Mutations in CEP104.

Joubert syndrome (JBTS) is a primarily autosomal-recessive disorder characterized by a distinctive mid-hindbrain and cerebellar malformation, oculomotor apraxia, irregular breathing, developmental delay, and ataxia. JBTS is a genetically heterogeneous ciliopathy. We sought to characterize the genetic landscape associated with JBTS in the French Canadian (FC) population. We studied 43 FC JBTS subjects from 35 families by combining targeted and exome sequencing. We identified pathogenic (n = 32 families) or possibly pathogenic (n = 2 families) variants in genes previously associated with JBTS in all of these subjects, except for one. In the latter case, we found a homozygous splice-site mutation (c.735+2T>C) in CEP104. Interestingly, we identified two additional non-FC JBTS subjects with mutations in CEP104; one of these subjects harbors a maternally inherited nonsense mutation (c.496C>T [p.Arg166*]) and a de novo splice-site mutation (c.2572-2A>G), whereas the other bears a homozygous frameshift mutation (c.1328_1329insT [p.Tyr444fs*3]) in CEP104. Previous studies have shown that CEP104 moves from the mother centriole to the tip of the primary cilium during ciliogenesis. Knockdown of CEP104 in retinal pigment epithelial (RPE1) cells resulted in severe defects in ciliogenesis. These observations suggest that CEP104 acts early during cilia formation by regulating the conversion of the mother centriole into the cilia basal body. We conclude that disruption of CEP104 causes JBTS. Our study also reveals that the cause of JBTS has been elucidated in the great majority of our FC subjects (33/35 [94%] families), even though JBTS shows substantial locus and allelic heterogeneity in this population.

Derivation and validation of a clinical decision rule to identify young children with skull fracture following isolated head trauma.

BACKGROUND: There is no clear consensus regarding radiologic evaluation of head trauma in young children without traumatic brain injury. We conducted a study to develop and validate a clinical decision rule to identify skull fracture in young children with head trauma and no immediate need for head tomography. METHODS: We performed a prospective cohort study in 3 tertiary care emergency departments in the province of Quebec. Participants were children less than 2 years old who had a head trauma and were not at high risk of clinically important traumatic brain injury (Glasgow Coma Scale score < 15, altered level of consciousness or palpable skull fracture). The primary outcome was skull fracture. For each participant, the treating physician completed a standardized report form after physical examination and before radiologic evaluation. The decision to order skull radiography was at the physician's discretion. The clinical decision rule was derived using recursive partitioning. RESULTS: A total of 811 patients (49 with skull fracture) were recruited during the derivation phase. The 2 predictors identified through recursive partitioning were parietal or occipital swelling or hematoma and age less than 2 months. The rule had a sensitivity of 94% (95% confidence interval [CI] 83%-99%) and a specificity of 86% (95% CI 84%-89%) in the derivation phase. During the validation phase, 856 participants (44 with skull fracture) were recruited. The rule had a sensitivity of 89% and a specificity of 87% during this phase. INTERPRETATION: The clinical decision rule developed in this study identified about 90% of skull fractures among young children with mild head trauma who had no immediate indication for head tomography. Use of the rule would have reduced the number of radiologic evaluations by about 60%.